US5483081A - Method for detecting light emitted by two surfaces of a stimulable phosphor sheet - Google Patents
Method for detecting light emitted by two surfaces of a stimulable phosphor sheet Download PDFInfo
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- US5483081A US5483081A US08/137,759 US13775993A US5483081A US 5483081 A US5483081 A US 5483081A US 13775993 A US13775993 A US 13775993A US 5483081 A US5483081 A US 5483081A
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- United States
- Prior art keywords
- stimulable phosphor
- phosphor sheet
- layer
- stimulating rays
- light
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/20—Measuring radiation intensity with scintillation detectors
- G01T1/2012—Measuring radiation intensity with scintillation detectors using stimulable phosphors, e.g. stimulable phosphor sheets
- G01T1/2014—Reading out of stimulable sheets, e.g. latent image
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
- G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/20—Measuring radiation intensity with scintillation detectors
- G01T1/2012—Measuring radiation intensity with scintillation detectors using stimulable phosphors, e.g. stimulable phosphor sheets
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
- G21K2004/04—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens with an intermediate layer
Definitions
- This invention relates to a method for detecting light emitted by two surfaces of a stimulable phosphor sheet, on which a radiation image has been stored.
- phosphors When certain kinds of phosphors are exposed to radiation such as X-rays, ⁇ -rays, ⁇ -rays, ⁇ -rays, cathode rays or ultraviolet rays, they store part of the energy of the radiation. Then, when the phosphor which has been exposed to the radiation is exposed to stimulating rays, such as visible light, light is emitted by the phosphor in proportion to the amount of energy stored thereon during its exposure to the radiation. A phosphor exhibiting such properties is referred to as a stimulable phosphor.
- stimulable phosphors in radiation image recording and reproducing systems. Specifically, a radiation image of an object, such as the human body, is stored on a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet). The stimulable phosphor sheet is then scanned with stimulating rays, such as a laser beam, which cause it to emit light in proportion to the amount of energy stored thereon during its exposure to the radiation.
- stimulating rays such as a laser beam
- the light emitted by the stimulable phosphor sheet when it is exposed to the stimulating rays is photoelectrically detected and converted into an electric image signal.
- the image signal is then processed and used during the reproduction of the radiation image of the object as a visible image, which has good image quality and can serve as an effective tool in, particularly, the efficient and accurate diagnosis of an illness.
- the ultimately obtained visible image may be reproduced as a hard copy or may be reproduced on a display device, such as a cathode ray tube (CRT) display device.
- CTR cathode ray tube
- a method for detecting light emitted by a stimulable phosphor sheet As a method for detecting light emitted by a stimulable phosphor sheet, a method has heretofore been known wherein a photoelectric read-out means for photoelectrically detecting the light emitted by the stimulable phosphor sheet is located only on the side of the stimulable phosphor sheet that is being scanned with the stimulating rays. The light emitted by one surface of the stimulable phosphor sheet is photoelectrically detected by the photoelectric read-out means. Also, a method for detecting light emitted by two surfaces of a stimulable phosphor sheet has been proposed in, for example, U.S. Pat. No. 4,346,295.
- two photoelectric read-out means are located on opposite sides of the stimulable phosphor sheet in order to photoelectrically detect the light emitted by the two surfaces of the stimulable phosphor sheet.
- the method for detecting light emitted by two surfaces of a stimulable phosphor sheet has the advantages in that the efficiency, with which the light emitted by the stimulable phosphor sheet is guided and detected, can be kept high as a whole, and a high signal-to-noise (S/N) ratio can be obtained.
- U.S. Pat. No. 4,394,581 discloses a technique wherein a radiation image storage panel (or a stimulable phosphor sheet) is colored with a coloring agent capable of selectively absorbing the stimulating rays such that an image having high sharpness can be obtained.
- various embodiments are described wherein the layers constituting the radiation image storage panel, such as a phosphor layer, a protective layer, and a substrate, are colored.
- this publication does not describe anything about how the radiation image storage panel should be colored when the operation for detecting light emitted by two surfaces of the radiation image storage panel is to be carried out, nor does it suggest anything about how the radiation image storage panel should be colored when the operation for detecting light emitted by two surfaces of the radiation image storage panel is to be carried out.
- Japanese Unexamined Patent Publication No. 2(1990)-112800 discloses a radiation image storage panel wherein a protective layer of the radiation image storage panel (or a stimulable phosphor sheet) is constituted of a material having fine light guiding path structures, which extend in a direction substantially normal to the surface of a phosphor layer, such that an image having good image quality can be obtained.
- this publication does not describe anything about the operation for photoelectrically detecting light emitted by two surfaces of the radiation image storage panel, nor does it suggest anything about the operation for detecting light emitted by two surfaces of the radiation image storage panel.
- the problems occur in that the stimulating rays, which are scanning the stimulable phosphor sheet, pass through the stimulable phosphor sheet, impinge upon the photoelectric read-out means located facing the back surface of the stimulable phosphor sheet, and are reflected by the photoelectric read-out means.
- the stimulating rays which have been reflected and diffused by the photoelectric read-out means, impinge upon the portions of the stimulable phosphor sheet other than the portion that is being scanned, and cause these portions of the stimulable phosphor sheet to emit light. Therefore, image information, which is not to be detected at a given instant, is photoelectrically detected at the given instant from the two surfaces of the stimulable phosphor sheet. As a result, the sharpness of the ultimately obtained image cannot be kept high.
- the primary object of the present invention is to provide a method for detecting light emitted by two surfaces of a stimulable phosphor sheet, wherein the sharpness of an ultimately obtained image is efficiently kept high.
- the present invention provides a first method for detecting light emitted by two surfaces of a stimulable phosphor sheet, comprising the steps of:
- the stimulable phosphor sheet comprising:
- a colored layer which is located on one side of the stimulable phosphor layer and contains a coloring agent, the coloring agent being capable of selectively absorbing stimulating rays, which cause the stimulable phosphor layer to emit light in proportion to the amount of energy stored thereon during its exposure to the radiation,
- the colored layer of the stimulable phosphor sheet may be located such that it may be in contact with the stimulable phosphor layer. Alternatively, a different layer may intervene between the colored layer and the stimulable phosphor layer. Also, for example, the colored layer may be located as a substrate or a protective layer such that it may be in contact with the stimulable phosphor layer. Alternatively, the colored layer may be located as an adhesive layer, which adheres a substrate or a protective layer to the stimulable phosphor layer. As another alternative, the colored layer may be located on the side outward from the substrate or the protective layer.
- the stimulable phosphor sheet which comprises the stimulable phosphor layer and the colored layer containing the coloring agent capable of selectively absorbing the stimulating rays.
- the stimulable phosphor sheet on which the radiation image has been stored, is scanned with the stimulating rays from the side opposite to the colored layer.
- the light which is emitted by the two surfaces of the stimulable phosphor sheet during the scanning of the stimulable phosphor sheet with the stimulating rays, is photoelectrically detected from the two surfaces of the stimulable phosphor sheet.
- the stimulating rays, which pass through the stimulable phosphor sheet, are absorbed by the colored layer, and therefore little stimulating rays impinge upon the photoelectric read-out means, which is located at the back surface of the stimulable phosphor sheet. Even if part of the stimulating rays is reflected by the photoelectric read-out means and again impinges upon the stimulable phosphor sheet, such stimulating rays will be absorbed by the colored layer, and therefore little stimulating rays will again impinge upon the stimulable phosphor layer. Therefore, portions of the stimulable phosphor of the stimulable phosphor layer other than the portion that is being scanned can be prevented from being stimulated by the stimulating rays. Accordingly, with the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention, the sharpness of an ultimately obtained image can be efficiently kept high.
- the stimulable phosphor sheet comprising:
- These materials have the properties such that they can confine light, which has entered from an input surface at an angle not larger than a specific angle (i.e. not larger than the maximum receptive angle) with respect to the line normal to the input surface, in regions inside of fine light guiding paths and can transmit the confined light to an output surface.
- Ulexite is a hydrous sodium potassium borate mineral.
- the crystal of ulexite is of the triclinic system and has the optical properties described above.
- the fiber optics plate (F. O. P.) is an optical element constituted of a plurality of fine fibers, each of which comprises a core glass having a high refractive index and a cladding glass having a low refractive index and covering the core glass, and which are fused together.
- the core diameter falls within the range of 6 ⁇ m to 25 ⁇ m.
- Either one of the two materials described above can be employed in the second method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention.
- ulexite has the drawbacks in that it is not easily available and in that the durability of the crystal is not high due to its brittleness and its slight solubility in water. Therefore, in the second method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention, the fiber optics plate should preferably be employed.
- the material described above can also confine light, which has entered from the output surface due to reflection, or the like, in the light guiding paths and can transmit the confined light to the input surface.
- the material is described in detail in Japanese Unexamined Patent Publication No. 2(1990)-112800.
- the stimulable phosphor sheet is scanned with the stimulating rays from the side opposite to the optical layer during the operation for reading out the radiation image stored on the stimulable phosphor sheet. Therefore, only the stimulating rays, which have passed through the stimulable phosphor layer and impinge at an angle not larger than the maximum receptive angle upon the optical layer, are confined in the fine light guiding paths and are radiated out of the stimulable phosphor sheet without being diffused.
- a photoelectric read-out means for detecting the light emitted by the stimulable phosphor sheet is located at the back surface of the stimulable phosphor sheet so as to stand facing a source of the stimulating rays with the stimulable phosphor sheet intervening therebetween.
- the stimulating rays which have been reflected and diffused by the photoelectric read-out means and which impinge at an angle larger than the maximum receptive angle of the optical layer, do not impinge upon the stimulable phosphor layer from the back surface of the stimulable phosphor sheet. Accordingly, the sharpness of the ultimately obtained image can be prevented from becoming low due to the stimulating rays, which are reflected by the photoelectric read-out means located at the back surface of the stimulable phosphor sheet and impinge upon the back surface of the stimulable phosphor sheet.
- FIG. 1 is a sectional view showing an example of a stimulable phosphor sheet employed in an embodiment of the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention
- FIG. 2 is a sectional view showing a different example of a stimulable phosphor sheet employed in an embodiment of the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention
- FIG. 3 is a schematic view showing an example of an X-ray image read-out apparatus
- FIG. 4 is a sectional view showing an example of a stimulable phosphor sheet employed in an embodiment of the second method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention
- FIG. 5 is an explanatory view showing a fiber optics plate, the view being taken from the direction of an input (or output) surface of the fiber optics plate.
- FIG. 1 is a sectional view showing an example of a stimulable phosphor sheet employed in an embodiment of the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention.
- a stimulable phosphor sheet 10 comprises a stimulable phosphor layer 12 and a protective layer 14, which is overlaid on one surface of the stimulable phosphor layer 12.
- the stimulable phosphor sheet 10 also comprises a colored layer 16, which is overlaid on the other surface of the stimulable phosphor layer 12 and which contains a coloring agent capable of selectively absorbing stimulating rays.
- the arrow X represents the direction, from which the stimulating rays are irradiated to the stimulable phosphor sheet 10 and scan it.
- the colored layer 16 may also serve as a substrate or a protective layer for the stimulable phosphor layer 12.
- the coloring agent contained in the colored layer 16 can selectively absorb the stimulating rays.
- FIG. 2 is a sectional view showing a different example of a stimulable phosphor sheet employed in an embodiment of the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention.
- a stimulable phosphor sheet 20 comprises a stimulable phosphor layer 22, and a protective layer 24, which is overlaid on one surface of the stimulable phosphor layer 22.
- the stimulable phosphor sheet 20 also comprises a colored layer 28, which is overlaid on the other surface of the stimulable phosphor layer 22 and which contains a coloring agent capable of selectively absorbing stimulating rays.
- the stimulable phosphor sheet 20 further comprises a protective layer (or a substrate) 26, which is overlaid on the colored layer 28.
- the arrow X represents the direction, from which the stimulating rays are irradiated to the stimulable phosphor sheet 20 and scan it.
- the colored layer 28 may also serve as an adhesive layer for adhering the protective layer (or the substrate) 26 to the stimulable phosphor layer 22.
- the colored layer 28 may be merely located as an intermediate layer.
- the protective layer (or the substrate) 26 may be overlaid directly on the other surface of the stimulable phosphor layer 22, and the colored layer 28 may be overlaid on the protective layer (or the substrate) 26 on the side opposite to the stimulable phosphor layer 22.
- the stimulable phosphor sheet is housed in a cassette, which blocks the stimulating rays, such as visible light.
- the stimulable phosphor sheet is used during an operation for recording an X-ray image.
- An X-ray source and the cassette, in which the stimulable phosphor sheet has been housed are located facing each other such that an object lying on an image recording table may intervene between the X-ray source and the cassette.
- the colored layer of the stimulable phosphor sheet housed in the cassette may be located on the front side or on the back side of the stimulable phosphor layer.
- X-rays are then produced by the X-ray source and irradiated to the object.
- FIG. 3 is a schematic view showing an example of an X-ray image read-out apparatus for photoelectrically reading out the X-ray image from the stimulable phosphor sheet 10, on which the X-ray image has been stored in the manner described above.
- the stimulable phosphor sheet 10 is placed on endless belts 49a and 49b such that the colored layer may face down.
- the endless belts 49a and 49b are rotated by motors (not shown).
- a laser beam source 41, a rotating polygon mirror 43, and a motor 42 are located above the stimulable phosphor sheet 10.
- the laser beam source 41 produces a laser beam serving as stimulating rays, which cause the stimulable phosphor sheet 10 to emit light in proportion to the amount of energy stored thereon during its exposure to the X-rays.
- the rotating polygon mirror 43 reflects and deflects the laser beam, which has been produced by the laser beam source 41, such that the laser beam may scan the stimulable phosphor sheet 10 in main scanning directions.
- a light guide member 45a is located above and close to the position on the stimulable phosphor sheet 10 which is being scanned with the laser beam.
- the light guide member 45a collects light, which is emitted by the stimulable phosphor sheet 10 when it is scanned with the laser beam, from above the stimulable phosphor sheet 10.
- a light guide member 45b is located below the position on the stimulable phosphor sheet 10 which is being scanned with the laser beam.
- the light guide member 45b is located perpendicularly to the stimulable phosphor sheet 10 and collects the light, which is emitted by the stimulable phosphor sheet 10 when it is scanned with the laser beam, from below the stimulable phosphor sheet 10.
- the light guide members 45a and 45b are located such that they may respectively be in close contact with photomultipliers 46a and 46b, which photoelectrically detect the light emitted by the stimulable phosphor sheet 10.
- the photomultipliers 46a and 46b are respectively connected to logarithmic amplifiers 47a and 47b.
- the logarithmic amplifiers 47a and 47b are connected to a memory 48.
- the X-ray image recording operation is carried out in the manner described above, and the X-ray image of the object is stored on the stimulable phosphor sheet 10.
- the stimulable phosphor sheet 10, on which the X-ray image has been stored is set at a predetermined position on the endless belts 49a and 49b.
- the stimulable phosphor sheet 10, which has been set at the predetermined position is conveyed by the endless belts 49a and 49b in a sub-scanning direction indicated by the arrow Y.
- the laser beam is produced by the laser beam source 41.
- the laser beam which has been produced by the laser beam source 41, is reflected and deflected by the rotating polygon mirror 43, which is quickly rotated by the motor 42 in the direction indicated by the arrow.
- the laser beam which has thus been reflected and deflected by the rotating polygon mirror 43, impinges upon the stimulable phosphor sheet 10 and scans it in the main scanning directions indicated by the double headed arrow X.
- the main scanning directions are approximately normal to the sub-scanning direction indicated by the arrow Y.
- the light, which is emitted upwardly by the stimulable phosphor sheet 10, is represented by reference numeral 44a.
- the light, which is emitted downwardly by the stimulable phosphor sheet 10, is represented by reference numeral 44b.
- the emitted light 44a is guided by the light guide member 45a and photoelectrically detected by the photomultiplier 46a.
- the light guide member 45a is made from a light guiding material, such as an acrylic plate.
- the light guide member 45a has a linear input end face, which is located such that it may extend along the main scanning line on the stimulable phosphor sheet 10, and a ring-like output end face, which is located such that it may be in close contact with a light receiving face of the photomultiplier 46a.
- the emitted light 44a which has entered from the input end face into the light guide member 45a, is guided through repeated total reflection inside of the light guide member 45a, emanates from the output end face, and is received by the photomultiplier 46a.
- the amount of the emitted light 44a representing the X-ray image is converted by the photomultiplier 46a into an electric signal.
- the emitted light 44b is guided by the light guide member 45b and is photoelectrically detected by the photomultiplier 46b.
- the stimulable phosphor sheet 10 which is employed in the embodiment of the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention, is provided with the colored layer 16 containing the coloring agent capable of selectively absorbing the stimulating rays.
- the stimulable phosphor sheet 10 is located with its colored layer 16 facing down such that the stimulable phosphor sheet 10 may be scanned with the stimulating rays from the side opposite to the colored layer 16 of the stimulable phosphor sheet 10.
- the stimulating rays which have been produced by the laser beam source 41 and have passed through the protective layer 14 and the stimulable phosphor layer 12, are absorbed by the colored layer 16 of the stimulable phosphor sheet 10. If the stimulating rays are radiated out of the back side of the stimulable phosphor sheet 10 and are reflected by the photoelectric read-out means, which is located on the back side of the stimulable phosphor sheet 10, the stimulating rays will again impinge upon the stimulable phosphor sheet 10. However, such stimulating rays are absorbed by the colored layer 16 and do not impinge upon the stimulable phosphor layer 12.
- the photomultiplier 46a generates an analog output signal S1.
- the analog output signal S1 is logarithmically amplified by the logarithmic amplifier 47a and is then fed into the memory 48.
- the analog output signal S1 is converted by an A/D converter into a digital signal, and a first image signal is thereby obtained.
- the photomultiplier 46b generates an analog output signal S2.
- the analog output signal S2 is logarithmically amplified by the logarithmic amplifier 47b and is then fed into the memory 48.
- the analog output signal S2 is converted by an A/D converter into a digital signal, and a second image signal is thereby obtained.
- the first and second image signals are added to each other by a calculating means of the memory 48, and an ultimate image signal is thereby obtained.
- the level of the ultimate image signal is proportional to the logarithmic value of the amount of the light emitted by each picture element on the stimulable phosphor sheet 10. In this manner, the light emitted by the stimulable phosphor sheet 10 during its exposure to the stimulating rays is detected from the two surfaces of the stimulable phosphor sheet 10. Therefore, the efficiency, with which the light emitted by the stimulable phosphor sheet 10 is guided and detected, can be kept high, and an image having a high S/N ratio can be obtained ultimately.
- the light guide member 45b guides the light, which is emitted by the stimulable phosphor sheet 10 without being adversely affected by the stimulating rays reflected and diffused by the light guide member 45b. Therefore, an image can be obtained which has a higher sharpness than that obtainable with a conventional method for detecting light emitted by two surfaces of a stimulable phosphor sheet.
- Stimulable phosphor sheets provided with stimulable phosphor layers colored with coloring agents have heretofore been used widely.
- the colored stimulable phosphor layer absorbs the stimulating rays, which pass through the stimulable phosphor sheet, and adverse effects from the stimulating rays reflected by a photoelectric read-out means, which is located on the back side of the stimulable phosphor sheet, can be reduced. Therefore, an image can be obtained which has as high a sharpness as that obtained with the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention.
- the coloring agent contained in the stimulable phosphor layer directly reduces the amount of the stimulating rays, which scan the stimulable phosphor sheet and impinge upon the stimulable phosphor layer. Accordingly, the amount of light emitted by the stimulable phosphor sheet becomes smaller, and the S/N ratio of the image signal obtained in this manner becomes lower than the S/N ratio obtained with the first method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention.
- FIG. 4 is a sectional view showing an example of a stimulable phosphor sheet employed in an embodiment of the second method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention.
- a stimulable phosphor sheet 110 comprises a stimulable phosphor layer 112 and a protective layer 114, which is overlaid on one surface of the stimulable phosphor layer 112.
- the stimulable phosphor sheet 110 also comprises an optical layer 116, which is overlaid on the other surface of the stimulable phosphor layer 112.
- the optical layer 116 is constituted of a material having fine light guiding path structures, which extend in a direction substantially normal to the surface of the stimulable phosphor layer 112.
- a protective layer or a substrate may be located on the side outward from the optical layer 116. In this embodiment, the optical layer 116 is located such that it may be in direct contact with the stimulable phosphor layer 112.
- a substrate, a protective layer, or an adhesive layer, which adheres the optical layer 116 and the stimulable phosphor layer 112 to each other, may be located between the optical layer 116 and the stimulable phosphor layer 112.
- any stimulable phosphor sheet may be employed which comprises the stimulable phosphor layer and the aforesaid optical layer located on one side of the stimulable phosphor layer.
- FIG. 5 is an explanatory view showing a fiber optics plate which constitutes the optical layer 116, the view being taken from the direction of an input (or output) surface of the fiber optics plate.
- a fiber comprises a core glass 122, which has a high refractive index, and a cladding glass 124, which has a low refractive index and which surrounds the core glass 122.
- a plurality of such fibers are located adjacent to one another with an absorber (E. M. A.) glass 126 intervening between adjacent fibers.
- the absorber glass 126 absorbs light, which goes from the core glass 122 through the cladding glass 124 to the exterior, or light impinging upon the cladding glass 124.
- light which has entered into a single fiber from its input surface, does not go to different fibers, and is confined in the region inside of the fine light guiding path (i.e. the fiber). The confined light is transmitted to the output surface of the fiber and is radiated to the side outward from the output surface of the fiber.
- the stimulable phosphor sheet is housed in a cassette, which blocks the stimulating rays, such as visible light.
- the stimulable phosphor sheet is used during an operation for recording an X-ray image.
- An X-ray source and the cassette, in which the stimulable phosphor sheet has been housed are located facing each other such that an object lying on an image recording table may intervene between the X-ray source and the cassette.
- the optical layer of the stimulable phosphor sheet housed in the cassette may be located on the front side or on the back side of the stimulable phosphor layer.
- X-rays are then produced by the X-ray source and irradiated to the object.
- An operation for reading out the X-ray image from the stimulable phosphor sheet 110, on which the X-ray image has been stored in the manner described above, is carried out in the same manner as that described above with reference to FIG. 3 for the stimulable phosphor sheet 10.
- the stimulable phosphor sheet 110 is placed on the endless belts 49a and 49b such that the optical layer (i.e. the fiber optics plate) may face down.
- the stimulable phosphor sheet 110 which is employed in the embodiment of the second method for detecting light emitted by two surfaces of a stimulable phosphor sheet in accordance with the present invention, is provided with the optical layer 116 capable of transmitting only light, which is incident from a direction substantially normal to the surface of the stimulable phosphor layer 112.
- the stimulable phosphor sheet 110 is located with its optical layer 116 facing down, and the stimulating rays are irradiated to the stimulable phosphor sheet 110 from the side of the protective layer 114.
- the stimulating rays which have been produced by the laser beam source 41 and have passed through the protective layer 114, the stimulable phosphor layer 112, and the optical layer 116, will be reflected by the light guide member 45b, which is located adjacent to the optical layer 116, and will again impinge upon the optical layer 116.
- the stimulating rays impinge upon the optical layer 116 at an angle larger than the maximum receptive angle of the optical layer 116 and, therefore, do not impinge upon the stimulable phosphor layer 12.
- the light guide member 45b guides the light, which is emitted by the stimulable phosphor sheet 110 without being adversely affected by the stimulating rays reflected and diffused by the light guide member 45b. Therefore, an image can be obtained which has a higher sharpness than that obtainable with a conventional method for detecting light emitted by two surfaces of a stimulable phosphor sheet.
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Abstract
Description
Claims (10)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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JP4-280285 | 1992-10-19 | ||
JP4-280286 | 1992-10-19 | ||
JP4280286A JP2952453B2 (en) | 1992-10-19 | 1992-10-19 | Double-sided condensing phosphor sheet reading method |
JP4280285A JP2987668B2 (en) | 1992-10-19 | 1992-10-19 | Double-sided condensing phosphor sheet reading method |
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US5483081A true US5483081A (en) | 1996-01-09 |
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US08/137,759 Expired - Lifetime US5483081A (en) | 1992-10-19 | 1993-10-19 | Method for detecting light emitted by two surfaces of a stimulable phosphor sheet |
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Cited By (18)
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US5550385A (en) * | 1994-10-14 | 1996-08-27 | Fuji Photo Film Co., Ltd | Method and apparatus for detecting abnormal image patterns |
WO1997042877A1 (en) * | 1996-05-13 | 1997-11-20 | University Of Massachusetts Medical Center | A system for quantitative radiographic imaging |
US5877508A (en) * | 1993-09-20 | 1999-03-02 | Fuji Photo Film Co., Ltd. | Radiation image storage panel |
US6075250A (en) * | 1996-08-27 | 2000-06-13 | Fuji Photo Film Co., Ltd. | Radiation image storage panel |
US6239448B1 (en) * | 1998-04-22 | 2001-05-29 | Fuji Photo Film Co., Ltd. | Radiation image read-out method and apparatus |
EP1137015A1 (en) * | 2000-03-23 | 2001-09-26 | Agfa-Gevaert N.V. | A storage phosphor screen with thick outermost layer and a method for using the same |
US6313477B1 (en) * | 1998-03-30 | 2001-11-06 | Fuji Photo Film Co., Ltd. | Method of and apparatus for reading radiation images and correcting shading and/or fading of the images |
US20030183777A1 (en) * | 2002-03-26 | 2003-10-02 | Luc Struye | Storage phosphor screen having binderless colored layers |
US20030226985A1 (en) * | 2000-04-18 | 2003-12-11 | Fuji Photo Film Co., Ltd. | Image information reading apparatus |
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US6313477B1 (en) * | 1998-03-30 | 2001-11-06 | Fuji Photo Film Co., Ltd. | Method of and apparatus for reading radiation images and correcting shading and/or fading of the images |
US6239448B1 (en) * | 1998-04-22 | 2001-05-29 | Fuji Photo Film Co., Ltd. | Radiation image read-out method and apparatus |
US6806486B2 (en) * | 1998-06-10 | 2004-10-19 | Fuji Photo Film Co., Ltd. | Radiation image read-out method and apparatus |
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US20030226985A1 (en) * | 2000-04-18 | 2003-12-11 | Fuji Photo Film Co., Ltd. | Image information reading apparatus |
US6740898B2 (en) * | 2000-09-11 | 2004-05-25 | Fuji Photo Film Company, Limited | Radiation image information read-out method and apparatus |
US6977385B2 (en) * | 2002-03-26 | 2005-12-20 | Agfa-Gevaert | Storage phosphor screen having binderless colored layers |
US20030183777A1 (en) * | 2002-03-26 | 2003-10-02 | Luc Struye | Storage phosphor screen having binderless colored layers |
US20060127002A1 (en) * | 2002-10-24 | 2006-06-15 | Franklin James B | Light transfer component |
US20060091320A1 (en) * | 2004-10-28 | 2006-05-04 | Eastman Kodak Company | Storage phosphor cassette |
US7087909B2 (en) | 2004-10-28 | 2006-08-08 | Eastman Kodak Company | Storage phosphor cassette |
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US7728817B2 (en) * | 2006-04-10 | 2010-06-01 | Avago Technologies Ecbu Ip (Singapore) Pte, Ltd. | Optical navigation system with multiplexed image processing |
WO2011149707A2 (en) * | 2010-05-25 | 2011-12-01 | American Science And Engineering, Inc. | Low-cost position-sensitive x-ray detector |
WO2011149707A3 (en) * | 2010-05-25 | 2012-01-26 | American Science And Engineering, Inc. | Low-cost position-sensitive x-ray detector |
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EP2579266A1 (en) * | 2010-06-04 | 2013-04-10 | Hamamatsu Photonics K.K. | Scintillator panel and radiation image sensor |
EP2579266A4 (en) * | 2010-06-04 | 2014-12-17 | Hamamatsu Photonics Kk | Scintillator panel and radiation image sensor |
US10458931B1 (en) | 2016-06-17 | 2019-10-29 | Leidos, Inc. | Contact imaging sensor head for computed radiography |
US10876981B2 (en) | 2016-06-17 | 2020-12-29 | Leidos, Inc. | Contact imaging sensor head for computed radiography |
US12044637B2 (en) | 2016-06-17 | 2024-07-23 | Leidos, Inc. | Contact imaging sensor head for computed radiography |
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